Find a good loupe and a bright contrasty object at least a 1.2 mile a way. A full moon is a good infinity target, a traffic light way down there will work too. Loosen the screws on the stops and pull them to the front of the bed.
Rack the focus rails all the way to the back and lock them.
Now push/pull/nudge the front standard until the target is sharp. Lock the standard and check again (it always moves) once the target is sharp and the standard is locked, slide the stops up to the standard and screw them down.